Using reverse micelle processing, ZnAl2O4 nanopowders were synthesized from a mixed precursor(consisting of Zn(NO3)2 and Al(NO3)3). The ZnAl2O4 was prepared by mixing the aqueous solution at a molar ratio of Zn : Al = 1 : 2. The average size and distribution of the synthesized powders with heat treatment at 600 oC for 2 h were in the range of 10-20 nm and narrow, respectively. The average size of the synthesized powders increased with increasing water to surfactant molar ratio. The XRD diffraction patterns show that the phase of ZnAl2O4 was spinel(JCPDS No. 05-0669). The synthesized and calcined powders were characterized using a thermogravimetric - differential scanning calorimeter(TG-DSC), X-ray diffraction analysis (XRD), and high resolution transmission electron microscopy(HRTEM). The effects of the synthesis parameter, such as the molar ratio of water to surfactant, are discussed.